Detection of cyanopolyynes in the protostellar shock L1157-B1

Detection of cyanopolyynes in the protostellar shock L1157-B1 Edgar Mendoza IAG/USP, S~ao Paulo B. Lefloch, C. Ceccarelli, A. Al-Edhari, J. Lepine, C. Codella, L. Podio, S. Viti, H. M. Boechat-Roberty, C. Kahane, R. Bachiller, M. Benedettini International Symposium and Workshop on Astrochemistry Campinas 07/07/2016

Index Cyanopolyynes in interstellar conditions ASAI: Line identification Formation of HC 3 N in L1157-B1 Summarizing

Cyanopolyynes in interstellar conditions Bell et al. (1997) determined a decrement between successive cyanopolyynes in TMC-1 Synthesis starting with small precursors C 2 H + 2, HCN, C 2H, HNC Freeman et al. (1978) 2016.

The source: L1157-B1 L1157-mm is a low-mass Class 0 protostar ( 250 pc) (left) Santangelo et al. 2013 (right) Map of L1157-B1 with HC 3 N J=16-15 L1157-B1, the brightest shock, is located at the second cavity in the south hemisphere L1157-B1 is a young object, its dynamical age is 4000 yr Several chemical species have been observed at mm wavelengths: H 2 CO, CH 3 OH, NH 2 CHO, CH 3 CN, H 2 S... Interferometric image of L1157-B1 HC 3 N J=16-15 (3.5 2.3 arcsec) Bachiller et al. (2001); Lefloch et al. (2012); Benedettini et al. (2013); Podio et al. (2014)

Physical components in B1 g 1 : T kin 250 K g 2 : T kin 70 K g 3 : T kin 25 K The source: L1157-B1 Busquet et al. (2014) and Lefloch et al. (2012)

Index Cyanopolyynes in interstellar conditions ASAI: Line identification Formation of HC 3 N in L1157-B1 Summarizing

The ASAI large program Astrochemical Surveys At Iram: 350 hours of observation at IRAM-30m (PIs: Lefloch & Bachiller 2014) Sources: Samples that cover all the evolutionary phases of solar type protostars Frequencies observed through ASAI: 3 mm: 80-116 GHz 2 mm: 130-170 GHz 1.3 mm: 200-320 GHz 0.8 mm: 329-350 GHz

Data reduction: Systematic study of HCN, HC 3 N and HC 5 N The data reduction was performed using the GILDAS/CLASS90 package. http://www.iram.fr/iramfr/gildas/ The CDMS and JPL spectroscopy databases were used to identify lines http://www.astro-uni-koel.de/cgi-bin/cdmssearch http://spec.jpl.nasa.gov/ftp/pub/catalog/catform.html The telescope and receiver paramenters: http://www.iram.es/irames/mainwiki/iram30mefficiencies

HC 3 N Cold component from HC 3 N J=8-7 to J=19-18 T rot = 16 K N = 3 ± 1 10 13 cm 2 Hot component from HC 3 N J=23-22 to J=32-31 T rot = 48 K N = 6 ± 2 10 12 cm 2 Detection of HC 3 N and HC 5 N

Detection of HC 3 N and HC 5 N HC 5 N Cold component from HC 3 N J=8-7 to J=19-18 T rot = 16 K N = 3 ± 1 10 13 cm 2 Hot component from HC 5 N J=36-35 to J=42-41 T rot 110 K N = 9 10 11 cm 2

Spectral line profile The high sensitivity of ASAI allowed to analyse the line profiles of HCN J=3-2, HCN J=1-0 and H 13 CN J=2-1 ( ) v I(v) exp v 0 v 0 12 km/s v 0 4 km/s v 0 2 km/s Lefloch et al. (2012) Gómez-Ruiz et al. (2015) Physical components 1. Component g1: T k = 210 K, N(CO)= 9 10 15 cm 2, size 10 2. Component g2: T k = 64 K, N(CO)= 9 10 16 cm 2, size 20 3. Component g3: T k = 23 K, N(CO)= 1 10 17 cm 2, size 25

HC 3 N isotopologues in B1: a subtle evidence H 13 CCCN Freq HC 13 CCN Freq HCC 13 CN Freq J MHz J MHz J MHz 10-9 88166 9-8 81534 10-9 90601 11-10 96983 10-9 90593 11-10 99661 12-11 105799 11-10 99651 12-11 108720 12-11 108710 Rotational temperatures around 15 K N(H 13 CCCN) N(H 13 CCCN) 1 10 12 cm 2 ; N(HCC 13 CN) 5 10 11 cm 2

Molecular abundances (preliminary results) Abundances derived from LTE and LVG calculations Component T kin n(h 2 ) N(CO) [HCN] [HNC] [HC 3 N] [HC 5 N] (K) 10 6 cm 3 10 16 cm 2 10 8 10 8 10 8 10 8 g1 200-300 0.8-1.5 0.48 42 - - - g2 50-70 0.1-1 7.0 69 0.19 1.3 0.13 g3 30 0.2-0.3 8.8 3.4 1.7 3.8 0.34 Next step: chemistry 1. What kind of processes govern the HC 3 N formation? 2. Can we find a match between the observations and chemical models? 3. Task: Chemical modelling of the physical components of B1

Index Cyanopolyynes in interstellar conditions ASAI: Line identification Formation of HC 3 N in L1157-B1 Summarizing

Chemical modelling: Formation of HC 3 N Phases Nahoon (Wakelam et al. 2012) was employed to compute the chemical abundances of HC3N and its precursors as a function of time. Dark-cloud conditions: T = 10 K, A v 10 mag, n(h 2 ) 10 4 cm 3, ζ = 3 10 16 s 1 High temperature phase: T 3000 K, A v 5-10 mag, n(h 2 ) 10 5 cm 3 Physical conditions of g2: T 70 K and A v 5-10 mag Initial abundances Specie Abundance He 0.14 N 7.4 10 5 O 3.52 10 4 C + 1.46 10 4 S + 1.60 10 7 Si + 1.60 10 8 Fe + 6.0 10 9 Na + 4.0 10 9 Mg + 1.4 10 8

Chemistry in the physical component g 2 1 st Step 2 nd Step Chemistry Elemental abundances Abundanes in steady-state e.g. Podio et al. 2014; Wakelam & Herbst 2008 (t = 1 10 6 yr) Physics n(h) = 2 10 4 cm 3 n(h) = 1 10 5 cm 3 T = 10 K T = 70 K A v = 10 mag A v = 10 mag ξ = 1-3 10 17 s 1 ξ = 1-3 10 16 s 1......

Chemistry in the physical component g 2

High temperature phase We kept the physical conditions except temperature. Models including: T =1000 K T =2000 K T =3000 K

Reactions working at high temperature

Sputtering of CH 4 Sakai et al. 2012; Codella et al. 2015 Large quantities of CH4 have been found around L1157-mm X(CH4) 0.4-1.5 10 5 What is the influence on the abundances when is injected CH4?

Sputtering of CH 4

Index Cyanopolyynes in interstellar conditions ASAI: Line identification Formation of HC 3 N in L1157-B1 Summarizing

Summarizing We confirmed through ASAI/IRAM-30m the presence of HC 3 N and HC 5 N in L1157-B1 Detection of HC 3 N from J=9-8 to J=32-31, HC 5 N from J=32-31 to J=43-42. The spectral line profiles of HNC J=1-0, HCN J=1-0 and HC 3 N = 9-8 evidenced the contribution of the g2 and g3 physical components, as reported by Lefloch et al. 2012 and Gómez-Ruiz et al. 2015 Component T kin N(CO) [HCN] [HNC] [HC 3 N] [HC 5 N] (K) 10 16 cm 2 10 8 10 8 10 8 10 8 g1 200-300 0.48 42 -- -- -- g2 50-70 7.0 69 0.19 1.3 0.13 g3 30 8.8 3.4 1.7 3.8 0.34